Air stream heater

ABSTRACT

Air stream heater, wherein a bush made of copper brass ( 5 ) is located in a metal housing ( 4 ) and in the axial boring of the bush a heating cartridge ( 6 ) is arranged and on the outer casing of the latter a spiral groove is arranged.

BACKGROUND OF THE INVENTION

This invention relates to the art of air stream heaters used for thetargeted supply of a hot air stream.

In prior art air stream heaters, a wire coil serves as a heating sourcefor the hot air, the coil being able to be heated up to a maximum of700° C., thereby heating up the air stream to the desired temperature.The air stream has a maximum volume of 2 m³/h and the max. air pressureis 1 bar (15 psi). On account of the restricted load capacity of theglowing wire coil this type of air stream heater has a limited servicelife (approx. 250 hrs.).

SUMMARY OF THE INVENTION

The air stream heater of the invention has a completely new concept. Thetechnical values are therefore fundamentally different:

1. Service life of over 1000 hours.

2. Maximum heated air volume 6 m³/h.

3. Max. pressure 2.5 bar (38 psi).

The invention provides an air stream heater, wherein a bush made ofcopper or brass (5) is located in a metal housing (4) and in the axialboring of the bush a heating cartridge (6) is arranged and on the outercasing of the latter a spiral groove is arranged.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevational view, partly in section, of the air streamheater of the invention; and

FIG. 2 is an enlarged fragmentary sectional view further illustratingthe air stream heater of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, in the centrical longitudinal axis of a metallicsquare housing (4) there is a boring in which a cylindrical bush (5) isarranged, the latter being made of brass or copper. In the innerlongitudinal boring of this bush (5) there is a heating cartridge (6).In the outer wall of the bush (5) there is a spiral groove (3). Arrangedin the wall at the front end of the housing (4) is a heat detector,which is for the purpose of temperature control of the air stream (2).The rear opening of the housing (4) is sealed by a cap (14) which isprovided with a centrical boring (9) and on the rear face of which aprotective cable (10) with an electric plug (11) are fastened. Theelectrical cables of the heat detector and the hearing cartridge (6) areconducted through the boring (9). The annular metal seal (8) at the rearend of the bush (5) prevents the escape of the air stream (2) out of thehousing (4). The elbow union (12) is for the purpose of connecting acompressed air line.

The air stream heater of the invention operates in the following manner.The first step is to connect a compressed air line with a pressurecontroller, a pressure gauge with the elbow union (12) and the electricplug (11) with an electronic temperature controller. The function of thetemperature controller is to set the desired temperature of the hot airstream. The compressed air controller provides a pressure setting of thehot air stream. The heat detector signals the temperature of the housing(4) to the electronic temperature controller and the latter transmitsthe on and off switching signals to the heating cartridge (6). Thelatter transfers the heat to the bush (5). The inflowing compressed air(2) flows through the spiral groove (3), is heated up in the process andleaves as a heated air stream through the nozzle (1).

1. An air stream heater, wherein a bush made of copper or brass (5) islocated in a metal housing (4) and in the axial boring of the bush aheating cartridge (6) is arranged and on the outer casing of the lattera spiral groove is arranged.
 2. The air stream heater according to claim1, wherein an output nozzle is in fluid communication with the spiralgroove.
 3. The air stream heater according to claim 1, wherein an inletfor receiving compressed air is in fluid communication with the spiralgroove.
 4. The air stream heater according to claim 1, wherein an inletfor receiving compressed air is in fluid communication with the spiralgroove upstream thereof and an outlet nozzle is in fluid communicationwith the spiral groove downstream thereof so that compressed air flowsthrough the spiral groove and is heated therein and leaves as a heatedair stream through the nozzle.